The isoalloxazine ring is a fundamental structural component of the flavin coenzymes, such as flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These coenzymes are derived from riboflavin (vitamin B2) and play a pivotal role in various biological redox reactions. The isoalloxazine ring system is known for its ability to undergo redox cycling, alternating between oxidized, reduced, and semiquinone states.
